Study: Alcohol, Not cannabis, Linked To Psychosis

Another nail has been firmly hammered into the coffin of cannabis myths: Results of a new long term study show that marijuana use isn’t linked to the development of mental disorders.

A four year study looking into the effects of alcohol, tobacco and cannabis use on the risk of psychosis has just been published in the journal Schizophrenia Research. Conducted by researchers at the University of Calgary, this new study followed 170 individuals deemed to be at a high risk of developing psychosis for four years, analyzing the use of those substances and how they affected mental health in the long run.

What they found was that the use of those substances was significantly higher in those with psychosis or schizophrenia than in those without it, but that there was no evidence to suggest that cannabis was actually linked to the development of any disorders. In fact, perhaps not surprisingly, what they did find was that if anything is causing the onset of psychosis, it is alcohol.

Jean Addington, the lead researcher and author wrote “Results revealed that low use of alcohol, but neither cannabis use nor tobacco use at baseline, contributed to the prediction of psychosis in the clinical high risk sample.”

This backs up a growing body of research, including some outlined in one of our previous blog posts, which suggests cannabis is not the causes of such illnesses. In fact, evidence is strongly pointing to the notion that the onset of psychosis is largely down to hereditary factors, largely shifting the blame from drugs altogether.

"Impact of substance use on conversion to psychosis in youth at clinical high risk of psychosis": http://www.schres-journal.com/article/S0920-9964(14)00193-5/abstract